-------- Original Message --------
Subject: Re: CVA and MANOVA
Date: Wed, 27 Feb 2008 08:02:38 -0800 (PST)
From: Cristian Correa <[EMAIL PROTECTED]>
To: <[email protected]>
References: <[EMAIL PROTECTED]>
Hi Amelia,
Comments from another beginner: I think you can use RW to reduce
dimensionality before conducting MANOVA. I don't see the problem, unless
you're severely violating assumptions (in which case you can do
NPMANOVA). It may (or may not) be more difficult to visualize the
results of your analyses (depending on the RW obtained and kept) because
you will be moving in the more integrated and distorted space of RW
compared to the more shape-comprehensive space of PW (using all PW).
You could use a few RW (e.g. the first two, if they account for much of
the variance) in a MANOVA for statistic test. Then do a CVA to visualize
significant differences between groups and get centroids for each group.
It is very likely that each CV axis will pick up a different RW more
heavily. In this case it is easy to interpret morphological differences
in each of the CV axes; you just have to move along the RW plots. I
don't think you can directly predict shape from the CVA using RW. Can you?
In summary, I would go for RW if I really need to reduce dimensionality,
otherwise I'd choose using the full set of PWs. But I'm a novice as well
and I'd love to see the answers of experts.
Buena suerte!
Cristian
----- Original Message -----
*From:* morphmet <mailto:[EMAIL PROTECTED]>
*To:* morphmet <mailto:[email protected]>
*Sent:* Wednesday, February 27, 2008 9:11 AM
*Subject:* CVA and MANOVA
-------- Original Message --------
Subject: CVA and MANOVA
Date: Wed, 27 Feb 2008 05:15:56 -0800 (PST)
From: M. Amelia Chemisquy <[EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>>
To: [email protected] <mailto:[email protected]>
Hi!
I'm using geometric morphometry for analyzing orchid seeds, and since I
am quite new at this (and at statistics two) I have a few questions. I
want to perform a CVA and a MANOVA with my morphometric results, and I
want to know if I can use the relative warps scores for doing this, or
it can only be done with the partial warps. What if I don´t fulfill the
number of samples (4 times the number of variables) needed, may I use
the relative warps in this case?
Besides, is there any way to obtain the deformation grids for the CVA
using any of the the tps software?
Thanks a lot!
Amelia
--
Lic. Amelia Chemisquy
Instituto de Botánica Darwinion
Casilla de Correo 22
B1642HYD, San Isidro
Argentina
Tel. (54 11) 4743 4800/4742 8534
[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>
www.darwin.edu.ar <http://www.darwin.edu.ar>
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